/Engine/Source/Editor/UnrealEd/Public/EditorModeTools.h
Called when the mouse is moved while a window input capture is in effect
true if input was handled
virtual bool CapturedMouseMove ( [FEditorViewportClient](API\Editor\UnrealEd\FEditorViewportClient) * InViewportClient, [FViewport](API\Runtime\Engine\FViewport) * InViewport, int32 InMouseX, int32 InMouseY )